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Cardiorespiratory optimal point during exercise testing is related to cardiovascular and all-cause mortality.
Laukkanen, JA, Kunutsor, SK, Araújo, CG, Savonen, K
Scandinavian journal of medicine & science in sports. 2021;(10):1949-1961
Abstract
Cardiorespiratory optimal point (COP) during exercise may be a potentially clinically useful cardiopulmonary exercise testing (CPET) variable, but its prognostic relevance for adverse cardiovascular disease (CVD) outcomes is unknown. We aimed to assess the association of COP during exercise with fatal mortality outcomes and the extent to which COP could improve the prediction of CVD mortality. Cardiorespiratory optimal point, the minimum value of the ventilatory equivalent for oxygen (VE/VO2) in a given minute of a CPET, was defined in 2,205 men who underwent CPET. Hazard ratios (HRs) (95% confidence intervals [CIs]) for outcomes and measures of risk discrimination for CVD mortality were calculated. During a median follow-up of 28.8 years, 402 fatal CHDs, 607 fatal CVDs, and 1,348 all-cause mortality events occurred. COP was continually associated with each outcome in a dose-response manner. On adjustment for established and emerging risk factors, the HRs (95% CIs) for fatal CHD, fatal CVD, and all-cause mortality were 3.05 (1.94-4.81), 2.82 (1.91-4.18) and 2.46 (1.85-3.27), respectively, per standard deviation increase in COP. After further adjustment for high sensitivity C-reactive protein, the HRs were 2.82 (1.78-4.46), 2.57 (1.73-3.81), and 2.27 (1.70-3.02), respectively. Addition of COP to a CVD mortality risk prediction model containing established risk factors was associated with a C-index change of 0.0139 (0.0040 to 0.0238; p = 0.006) at 25 years. COP during exercise is directly associated with fatal cardiovascular and all-cause mortality events in dose-response fashions. COP during exercise may improve the prediction of the long-term risk for CVD mortality.
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Retinal oximetry and fractal analysis of capillary maps in sickle cell disease patients and matched healthy volunteers.
Birkhoff, WAJ, van Manen, L, Dijkstra, J, De Kam, ML, van Meurs, JC, Cohen, AF
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2020;(1):9-15
Abstract
PURPOSE Fractal analysis can be used to quantitatively analyze the retinal microvasculature and might be a suitable method to quantify retinal capillary changes in sickle cell disease (SCD) patients. Retinal oximetry measurements might function as a proxy for the pathophysiology of cerebrovascular diseases. Moreover, hypoxia has an important role in the pathophysiology of diabetic and other retinopathies. However, little is known about the oximetry around the macula in SCD patients. With this study, we explored the feasibility to perform these quantified measurements in SCD patients. METHODS Retinal microvascular and oximetry measurements were performed in eight SCD patients and eight healthy matched controls. Oximetry pictures and non-invasive capillary perfusion maps (nCPM) were obtained by the retinal function imager. Measurements were conducted twice on two different study days. Measured variables included monofractal dimension (Dbox), relative saturation, deoxygenated hemoglobin (deoxyHb), and oxygenated hemoglobin (oxyHb) concentration. RESULTS No statistically significant differences in vessel density were found in the different annular zones (large vessels, p = 0.66; small vessels, p = 0.66) and anatomical quadrants (large vessels, p = 0.74; small vessels, p = 0.72). Furthermore, no significant between-group differences were found in the other different anatomical quadrants and annular zones around the fovea for relative saturation levels and deoxygenated Hb. However, the oxyHb levels were significantly lower in SCD patients, compared with those in matched controls in the temporal quadrants (p = 0.04; p = 0.02) and the superior nasal quadrant (p = 0.05). CONCLUSIONS Our study demonstrated the feasibility of multispectral imaging to measure retinal changes in oxygenation in both SCD patients and matched volunteers. The results suggest that in SCD patients before any structural microvascular changes in the central retina are present, functional abnormalities can be observed with abnormal oximetry measurements.
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3.
Lower early postnatal oxygen saturation target and risk of ductus arteriosus closure failure.
Inomata, K, Taniguchi, S, Yonemoto, H, Inoue, T, Kawase, A, Kondo, Y
Pediatrics international : official journal of the Japan Pediatric Society. 2016;(11):1153-1157
Abstract
BACKGROUND Early postnatal hyperoxia is a major risk factor for retinopathy of prematurity (ROP) in extremely premature infants. To reduce the occurrence of ROP, we adopted a lower early postnatal oxygen saturation (SpO2 ) target range (85-92%) from April 2011. Lower SpO2 target range, however, may lead to hypoxemia and an increase in the risk of ductus arteriosus (DA) closure failure. The aim of this study was therefore to determine whether a lower SpO2 target range, during the early postnatal stage, increases the risk of DA closure failure. METHODS Infants born at <28 weeks' gestation were enrolled in this study. Oxygen saturation target range during the first postnatal 72 h was 84-100% in study period 1 and 85-92% in period 2. RESULTS Eighty-two infants were included in period 1, and 61 were included in period 2. The lower oxygen saturation target range increased the occurrence of hypoxemia during the first postnatal 72 h. Prevalence of DA closure failure in period 2 (21%) was significantly higher than that in period 1 (1%). On multivariate logistic regression analysis, the lower oxygen saturation target range was an independent risk factor for DA closure failure. CONCLUSION Lower early postnatal oxygen saturation target range increases the risk of DA closure failure.
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Inertial sensors to estimate the energy expenditure of team-sport athletes.
Walker, EJ, McAinch, AJ, Sweeting, A, Aughey, RJ
Journal of science and medicine in sport. 2016;(2):177-81
Abstract
OBJECTIVES To quantify the energy expenditure of Australian Football training and matches and the total daily energy expenditure of Australian Football players using tri-axial accelerometers. DESIGN Cross sectional observation study. METHODS An algorithm was developed for the MiniMax 4.0 (Catapult Innovations, Scoresby Australia) using measured oxygen uptake and accelerometer data to estimate energy expenditure of 18 Australian Football players during training and matches. The algorithm was used to validate a metabolic power calculation used by Catapult Innovations (Scoresby Australia) in their proprietary GPS software. The SenseWear™ (Model MF-SW, Bodymedia, Pittsburgh, PA) armband was used to determine non-exercise activity thermogenesis and was worn for 7 days leading into a match. Training, match and non-exercise activity thermogenesis data was summed for total daily energy expenditure. RESULTS Energy expenditure for field training was estimated to be 2719±666kJ and for matches to be 5745±1468kJ. The estimated energy expenditure in the current study showed a large correlation (r=0.57, 90% CI 0.06-0.84) with the metabolic power calculation. The mean total daily energy expenditure for an in-season main training day was approximately 18,504kJ and match day approximately 19,160kJ with non-exercise activity thermogenesis contributing approximately 85% and 69% on training and match days, respectively. CONCLUSIONS The MiniMax 4.0 and SenseWear™ armband accelerometers provide a practical, non-invasive and an effective method to successfully measure training and match energy expenditure, and non-exercise activity thermogenesis in field sport athletes. Taking methodological limitations into consideration, measuring energy expenditure allows for individualised nutrition programming to enhance performance and achieve body composition goals.
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Does the incremental shuttle walk test require maximal effort in young obese women?
Jürgensen, SP, Trimer, R, Di Thommazo-Luporini, L, Dourado, VZ, Bonjorno-Junior, JC, Oliveira, CR, Arena, R, Borghi-Silva, A
Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas. 2016;(8)
Abstract
Obesity is a chronic disease with a multifaceted treatment approach that includes nutritional counseling, structured exercise training, and increased daily physical activity. Increased body mass elicits higher cardiovascular, ventilatory and metabolic demands to varying degrees during exercise. With functional capacity assessment, this variability can be evaluated so individualized guidance for exercise training and daily physical activity can be provided. The aim of the present study was to compare cardiovascular, ventilatory and metabolic responses obtained during a symptom-limited cardiopulmonary exercise test (CPX) on a treadmill to responses obtained by the incremental shuttle walk test (ISWT) in obese women and to propose a peak oxygen consumption (VO2) prediction equation through variables obtained during the ISWT. Forty obese women (BMI ≥30 kg/m2) performed one treadmill CPX and two ISWTs. Heart rate (HR), arterial blood pressure (ABP) and perceived exertion by the Borg scale were measured at rest, during each stage of the exercise protocol, and throughout the recovery period. The predicted maximal heart rate (HRmax) was calculated (210 - age in years) (16) and compared to the HR response during the CPX. Peak VO2 obtained during CPX correlated significantly (P<0.05) with ISWT peak VO2 (r=0.79) as well as ISWT distance (r=0.65). The predictive model for CPX peak VO2, using age and ISWT distance explained 67% of the variability. The current study indicates the ISWT may be used to predict aerobic capacity in obese women when CPX is not a viable option.
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6.
Effects of sodium bicarbonate correction of metabolic acidosis on regional tissue oxygenation in very low birth weight neonates.
Mintzer, JP, Parvez, B, Alpan, G, LaGamma, EF
Journal of perinatology : official journal of the California Perinatal Association. 2015;(8):601-6
Abstract
OBJECTIVE To determine the effects of sodium bicarbonate (NaHCO3) correction of metabolic acidosis on cardiopulmonary, laboratory, and cerebral, renal and splanchnic regional oxygen saturation (rSO2) and fractional tissue oxygen extraction (FTOE) in extremely premature neonates during the first postnatal week. STUDY DESIGN Observational cohort data were collected from 500 to 1250 g neonates who received NaHCO3 'half' corrections (0.3 * Weight (kg) * Base Deficit (mmol l(-1))) for presumed renal losses. RESULT Twelve subjects with normal blood pressure and heart rate received 17 NaHCO3 corrections. Mean (±s.d.) gestational age was 27±2 week and birth weight was 912±157 g. NaHCO3 corrections provided a mean (±s.d.) 4.5±1.0 ml kg(-1) fluid bolus, shifted mean (±s.d.) base deficit from 7.6±1.8 to 3.4±2.1 mmol l(-1) (P<0.05), and increased median (±s.d.) pH from 7.23±0.06 to 7.31±0.05 (P<0.05). No significant changes in blood pressure, pulse oximetry, PCO2, lactate, sodium, blood urea nitrogen, creatinine or hematocrit were observed. Cerebral, renal and splanchnic rSO2 (74%, 66% and 44%, respectively, at baseline) and FTOE (0.21, 0.29 and 0.52, respectively, at baseline) were unchanged following NaHCO3 correction. CONCLUSION NaHCO3 infusions decreased base deficits and increased pH though produced no discernible effects or benefits on cardiopulmonary parameters including rSO2 and FTOE. These findings warrant further prospective evaluation in larger populations with more significant metabolic acidosis to determine the utility of tissue oxygenation monitoring in differentiating metabolic acidosis due to oxygen delivery/consumption imbalance versus renal bicarbonate losses.
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Maternal antihypertensive drugs may influence cerebral oxygen extraction in preterm infants during the first days after birth.
Verhagen, EA, Kooi, EM, van den Berg, PP, Bos, AF
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2013;(9):871-6
Abstract
OBJECTIVE To determine whether maternal antihypertensive drugs influenced cerebral oxygenation in preterm infants during the first days after birth. METHODS We included 49 preterm infants (median gestational age 30.3 weeks, (range 26.0-31.9), birth weight 1250 g (560-2250)). Regional cerebral oxygen saturation (rcSO2) was measured by near-infrared spectroscopy on postnatal days 1, 2, 3, 4 and 5. Fractional tissue oxygen extraction (FTOE) was calculated using rcSO2 and arterial oxygen saturation (SpO2) values:(SpO2 - rcSO2)/SpO2. RESULTS Nine mothers were treated with labetalol and/or MgSO4 during pregnancy, three mothers with labetalol, MgSO4 and nifedipine, and 19 mothers with nifedipine only. Eighteen infants served as controls. Multivariate linear regression analysis showed that exposure to labetalol and/or MgSO4 during pregnancy decreased FTOE on day 1 after birth, while nifedipine did not. CONCLUSIONS Treating pregnant women with labetalol and/or MgSO4 may influence cerebral oxygen extraction in their offspring shortly after birth.